Attic Knee Wall Construction

The higher the knee wall the greater the amount of useful wall space you create in your finished attic.

Attic knee wall construction.

What are knee walls. The bottom plate of the knee wall rests on top of the floor joists leaving a large pathway for attic air to come up into the air cavity of the knee wall. A knee wall is a short vertical wall roughly two or three feet high that blocks in that useless triangular space. Install a top and bottom plate or blocking at the top and bottom of all knee wall cavities.

If you aren t sure whether or not your attic contains knee walls go and look around the edges. When insulated and covered with drywall the walls improve the thermal envelope of an attic. Install insulation without misalignments compressions gaps or voids in all knee wall cavities. But you do so at the expense of floor space.

Framing basics for attic knee walls along the sides of your loft or attic space. Support and follow me. The knee wall will be built on the floor of the attic and then tipped into place against the rafters. You can see the image below for an example of a knee wall.

Knee walls are short usually wooden walls installed around the sides of an attic where the rafters meet the floor. Secondly without an air barrier on the back of the knee wall and with the potential to sag as indicated above attic air goes around the insulation into the cavity on the vertical space as well. Scribe a line on your scrap piece along the angle formed by the rafter. Determine the angle of rafters by setting the scrap piece of 2x4 in a vertical position against the side of a rafter.

Knee walls are short wood framed walls that install between the ceiling joists and rafters in an attic.